The adsorption mechanism of carbon dioxide (CO₂) in the coal matrix is significant in practical stability and migration process of CO₂ into a coalbed seam. This study presents the kinetic investigation and the main controlling step of CO₂ adsorption capacity onto Malaysian coals. The experimental data of CO₂ adsorption were determined using a volumetric technique at 273, 298, 308, and 318 K and pressures up to 99.3 kPa. The experimental data of CO₂ adsorption was studied using kinetic based thermodynamic models. Fourier Transform Infrared Spectroscopy and X−Ray Diffraction analyses were performed for the coal samples characterization. The major functional group in all coal samples is hydroxyl (−OH) functional group. X−Ray Diffraction analysis has shown that the coal samples possessed one major peak assigned to quartz (d = 3.348 Å). The experimental results were correlated using kinetic models, which include pseudo−first−order, pseudo−second−order, Avrami, and Intra-particle diffusion models. The Intra−particle diffusion model was found in the best compliance with the experimental data. Therefore, the pore−diffusion is considered to be the primary limiting step for CO₂ interaction with the coal matrix. This indicated that the molecules of CO₂ transferred rapidly from the bulk to the surface of coal matrix and slowly diffused into pores of the coal matrix. The obtained results demonstrated that the overall CO₂ interaction with the coal matrix is influenced by the diffusion limiting step. The value of activation energies for all studied coal samples is lower than 8 kJ/mol. This showed that CO₂ adsorption onto all investigated coal samples is driven by a physical adsorption process.

煤基质中二氧化碳（CO ₂）的吸附机理对实际稳定性和CO ₂进入煤层的迁移过程具有重要意义。这项研究提出了动力学研究和对马来西亚煤上CO ₂吸附能力的主要控制步骤。使用体积技术在273、298、308和318 K以及压力高达99.3 kPa的条件下确定了CO ₂吸附的实验数据。CO ₂的实验数据使用基于动力学的热力学模型研究吸附。对煤样品进行了傅里叶变换红外光谱和X射线衍射分析。所有煤样品中的主要官能团是羟基（-OH）官能团。X射线衍射分析表明，煤样品具有一个分配给石英的主峰（d  = 3.348Å）。使用动力学模型将实验结果进行关联，其中包括伪一级，伪二级，Avrami和粒子内扩散模型。发现粒子内扩散模型最符合实验数据。因此，孔扩散被认为是CO ₂的主要限制步骤与煤基质的相互作用。这表明CO ₂分子从主体迅速转移到煤基质的表面，然后缓慢扩散到煤基质的孔隙中。所得结果表明，CO ₂与煤基质的整体相互作用受扩散限制步骤的影响。所有研究的煤样品的活化能值均低于8 kJ / mol。这表明CO ₂吸附到所有研究的煤样品上都是由物理吸附过程驱动的。